On Fri, Feb 23, 2024 at 11:09 AM Yu Kuai <yukuai1@xxxxxxxxxxxxxxx> wrote:
>
> Hi,
>
> 在 2024/02/20 23:30, Xiao Ni 写道:
> > stripe_ahead_of_reshape is used to check if a stripe region cross the
> > reshape position. So first, change the function name to
> > stripe_across_reshape to describe the usage of this function.
> >
> > For reshape backwards, it starts reshape from the end of array and conf->
> > reshape_progress is init to raid5_size. During reshape, if previous is true
> > (set in make_stripe_request) and max_sector >= conf->reshape_progress, ios
> > should wait until reshape window moves forward. But ios don't need to wait
> > if max_sector is raid5_size.
> >
> > And put the conditions into the function directly to make understand the
> > codes easily.
> >
> > This can be reproduced easily by lvm2 test shell/lvconvert-raid-reshape.sh
> > For dm raid reshape, before starting sync thread, it needs to reload table
> > some times. In one time dm raid uses MD_RECOVERY_WAIT to delay reshape and
> > it doesn't start sync thread this time. Then one io comes in and it waits
> > because stripe_ahead_of_reshape returns true because it's a backward
> > reshape and max_sectors > conf->reshape_progress. But the reshape hasn't
> > started. So skip this check when reshape_progress is raid5_size
>
> Like I said before, after following merged patch:
>
> ad39c08186f8 md: Don't register sync_thread for reshape directly
Hi Kuai
The reason I send this patch set is I don't agree the patch 01 of your
patch set. Does the patch (md: Don't register sync_thread for reshape
directly) rely on patch 01 from your patch set? Because your patch 01
only changes one logic and other patches rely on it. So it's the
reason I can't accept the following patches.
Regards
Xiao
>
> You should not see that sync_thread fo reshape is registered while
> MD_RECOVERY_WAIT is set, so this patch should not be needed.
>
> Thanks,
> Kuai
>
> >
> > Fixes: 486f60558607 ("md/raid5: Check all disks in a stripe_head for reshape progress")
> > Signed-off-by: Xiao Ni <xni@xxxxxxxxxx>
> > ---
> > drivers/md/raid5.c | 22 ++++++++++------------
> > 1 file changed, 10 insertions(+), 12 deletions(-)
> >
> > diff --git a/drivers/md/raid5.c b/drivers/md/raid5.c
> > index 8497880135ee..4c71df4e2370 100644
> > --- a/drivers/md/raid5.c
> > +++ b/drivers/md/raid5.c
> > @@ -5832,17 +5832,12 @@ static bool ahead_of_reshape(struct mddev *mddev, sector_t sector,
> > sector >= reshape_sector;
> > }
> >
> > -static bool range_ahead_of_reshape(struct mddev *mddev, sector_t min,
> > - sector_t max, sector_t reshape_sector)
> > -{
> > - return mddev->reshape_backwards ? max < reshape_sector :
> > - min >= reshape_sector;
> > -}
> > -
> > -static bool stripe_ahead_of_reshape(struct mddev *mddev, struct r5conf *conf,
> > +static sector_t raid5_size(struct mddev *mddev, sector_t sectors, int raid_disks);
> > +static bool stripe_across_reshape(struct mddev *mddev, struct r5conf *conf,
> > struct stripe_head *sh)
> > {
> > sector_t max_sector = 0, min_sector = MaxSector;
> > + sector_t reshape_pos = 0;
> > bool ret = false;
> > int dd_idx;
> >
> > @@ -5856,9 +5851,12 @@ static bool stripe_ahead_of_reshape(struct mddev *mddev, struct r5conf *conf,
> >
> > spin_lock_irq(&conf->device_lock);
> >
> > - if (!range_ahead_of_reshape(mddev, min_sector, max_sector,
> > - conf->reshape_progress))
> > - /* mismatch, need to try again */
> > + reshape_pos = conf->reshape_progress;
> > + if (mddev->reshape_backwards) {
> > + if (max_sector >= reshape_pos &&
> > + reshape_pos != raid5_size(mddev, 0, 0))
> > + ret = true;
> > + } else if (min_sector < reshape_pos)
> > ret = true;
> >
> > spin_unlock_irq(&conf->device_lock);
> > @@ -5969,7 +5967,7 @@ static enum stripe_result make_stripe_request(struct mddev *mddev,
> > }
> >
> > if (unlikely(previous) &&
> > - stripe_ahead_of_reshape(mddev, conf, sh)) {
> > + stripe_across_reshape(mddev, conf, sh)) {
> > /*
> > * Expansion moved on while waiting for a stripe.
> > * Expansion could still move past after this
> >
>
